Transfer RNA is an integral part of the cell's protein synthesizing system. The biochemical reactions in which tRNA is involved are well documented. However, the nature of the physical interaction of tRNA with other molecules involved in protein synthesis is essentially unknown. Carbon-13 NMR spectroscopy can be used to study structural and functional interactions of tRNA with other molecules and spectra would be more resolved than the corresponding proton NMR spectra. We have specifically enriched tRNA carbon-13 by growing a methionine auxotroph of Escherichia coli in medium with methnione-(methyl (13C)). Specific species of (13C)-enriched tTNA have been pruified. Labeling the tRNA with (13C)-methyl groups is advantageous because such groups occupy specific, known sites in the tRNA nucleotide sequence, are natural to the molecule and create NMR spectral signals at regions of the spectrum free from ribose and major base interference. Carbon-13 NMR spectroscopy of specific species of (13C) enriched tRNA will be used to study the interaction of other nucleic acids and proteins with tRNA at the sites of (13C)- methyl groups, C2 of adenine, uracil and cytosine and other carbons.